Method and apparatus for riveting



July 16, 1929. I 5, F, TAPMAN 1,721,263

METHOD ND APPARATUS FOR RIVETING Filed Aug. 20, 1927 2 sneetsshez 1 Fig.1

4 mm A IIIIIIIIflI/IIIIIIIIIIIIIIIIIIIII c July 16, 1929. s. F. TAPMAN 1.721,263

' METHOD AND APPARATUS FOR RIVETING Filed Aug. 20, 1927 2 Sheets-Sheet 2 Patented July 16, 1929.

r 1,721,263 "UNITEDL S PA E O SAMUEL I TAPMAN, OF JAMAICA, NEW YORK.

METHOD AND'APPARATUS FOR RIVETING.

Application filed August 20, 1927. Serial No. 214,296.

The present invention relates to methods of riveting and deals more particularly with such methods when applied in service requiring rapid work and an unfailing uniformity of excellence of the finished product.

WVhere a greatamount of rivetingis to be done theexpense of handling the materials in the drilling or punching, and riveting operationsisa considerable proportion of the total cost of the finished work and many forms of punches, drills and riveters have been designed in an effort to reduce the time required for doing the work. As a matter requiring further consideration, the strength of the joint under shearing stresses requires that the piece be designed with a suflicient quantity ofmetal to compensate forthat removed in the, drilling or punching operations. j

i This invention deals with thesetwo factors and an object thereof is to provide a method and apparatus for riveting whereby the handling of the piece is reduced appreciably thereby cutting down the expense of the total operation. It is proposed to eliminate the step of drilling and, instead, force the rivet through the pieces to be joined while the latter are highlyiheated.

A further object lies in preserving the original quantity of metal in the pieces, as Well as forcingit under the rivet heads to cause it to, fill all available space thereunder. In this manner the maximum strength of the joint is obtained as well as utilizing. all iof the metal in the pieces to be joined. l i

Other objects of the invention will be apparent as the description proceeds and reference will now be had, for amore detailed description of the invention, to the accompanying drawings wherein Figure 1 is a view in elevation, partly in section, showing a device in which the invention has been embodied in a known form of bull press, the work being in place, and

r the means for vheating it bearing there-- against to bring it to the desired tempera ture. t

Figure 2 is a sectional view taken on line 2-2 of Figure l and looking in the direction of the arrows. I

Figure 3 is a view in section taken on line 33 of Figure 2 and looking, in the direction of the arrows. j

Referring to the drawings a indicates a bull press of the usual form provided with a device I) forapplying' power to the riveting plunger. In this instance, the power source is shown with a cylinder provided with a piston adapted to be moved under air pres sure and controlled by hand lever b. A

connecting rod 19 is pivotally connected to a link 6 which is pivoted at 6 upon the stationary portion of the press. A suitable plunger a is slidably carried in the upper head of the bull press a and is connected, through link of, to the pivot point of link 6 and connecting rod 5 From the above description, it will be apparent that outward movement of connecting rod 6 will cause a downward movement of plunger a and the a desired riveting operation is thereby accomplished. v j j A slot a is provided in the bearing for the plunger in the upper head of the bull press, and a pin at carried by the plunger a moves in this slot.

In securing the ipieces together by means i of the rivet, the ormer are placed in the proper position asfshown in Figure 1 and indicated at 0. A rivet (Z is placed at the head of the plunger a and, when the work has been heated to the proper temperature, the plunger is moved downwardly to force the rivet through the highly heated work.

A device for' heatingthe work and riveting includes a bracket 6, carrying, pivotally, a guide member e"for an electrode holder 6 A forked lever e is pivoted with the guide 6 uponthe bracket eandis formed with a rearwardly extending cam arm etwhich is normally disposed in thepath of movement of the pin a The electrode holder 6 is provided with a head a carrying diametrically disposed rollers e. Springs (2 aid the force of gravity in restoringrthe electrode andrelated parts 'to the normal position shown in full lines in Figure 2. These rollers engage the upper faces of the forked port-ions of lever 6 and permit relative movement between ,the head 6 and forked lever 6 when the latter is moved pivotally from the descending plunger The sta- V tionary portion a of the bull press a is connected to a suitable source of electricity 9 which, preferably, is of low voltage and capable of supplying an extremely high current. The electrode f is also connected to the other side of this current supply and insulated from the conducting parts of the mechanism which are carried by the press.

When the electrode f is moved under influence of the spring e into engagement with the work 0 and the. rivet d, the circuit is closed through the work and rivet, and the current flow therethrough heats them to the desired temperature. Due to the fact that the area of contact between the electrode andrivet d is relatively small, a proportionately smaller amount of current will pass through the rivet and, as a consequence, the rivet will not be heated as highly as the work. The time of contact of the electrode with the rivet and work is designed to be sufficiently long to bring the work to an eX-- tremely hightemperature, at which the rivet may be forced through with little difficulty. The heating of the rivet, during this time, is suflicient to bring it to a cherry heat-and permit it to be headed in the proper manner as it is forced through the work.

' rivet when the latter is forced through the former and headed, the metal around the rivet will be forced into intimate contact with every available portion'thereof. This increases the strength of the joint against shear and the resulting work is much stronger due to this fact, as well as the fact that no metal has been removed from the work. i

The operation described above can be performed in less than six seconds and it will be quite apparent that a great saving results in the handling of the work, since it is unnecessary to perform the drilling operation. Theinvention is not to be construed as limited to the form of apparatus shown and described herein, since many constructions may be provided to perform the steps in the method embodied herein, and the specific mechanism described has been used merely as an example of one form in order that the invention might be described more clearly.

I claim as my invention:

1. The method of riveting comprising,

placing the workin the desired position,

that of the work, forcing the rivet through the work, and heading the rivet.

3. The method of riveting comprising,

placing the work in the desired position,

heating it to a. working temperature, heating the rivet simultaneously, forcing the rivet through the work, and heading the rivet.

4. The method of riveting comprising, placing the work in the desired position, placing the rivet over the work in a position to be forced into place, simultaneously heating the rivet and work to different tem peratures, forcing the rivet through the work,.and heading the rivet to compress the work between the heads thereof.

5. A device of the character described comprising means for holding the work, means for applying heat thereto to bring it to a working temperature, means for heating the rivet, means for forcing the rivet through the work, and means for heading the rivet.

6. A device of the character described comprising means for holding the work, means for applying heat thereto to bring it to a working temperature, means for heating the rivet to a temperature lower than that of the work, means for forcing the rivet through the work and means for heading the rivet.

7. A device of the character described comprisingmeans for holding the work, means for applying heat thereto to bring it to a working temperature, means for heating the rivet simultaneously, means for forcing the rivet through the. work and means for heading the rivet.

8. A device of the character described comprising means for holding the work, an electrode, means for placing the electrode over the portion of the work to be riveted and engage the rivet simultaneously, means for passing current from the electrode through the work and rivet to heat them to the desired temperatures, means for forcing the rivet through the work and means'for heading the rivet.

9. A device of the character described comprising means for holding thework, an electrode, means'for placing the electrode over theportion of the work to be riveted and engage the rivet simultaneously, the

area of the rivet engaged by the electrode being smaller than the area of the work engaged thereby, means for passing current from the electrode through the work and rivet, a smaller quantity passing through the rivet than through the work due to the different contact areas thereof, means for forcing the rivet through the work and means for heading the rivet.

This specification signed this 18th day of August, A. D. 1927.

SAMUEL F. TAPMAN. 

